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11-15-2015, 06:20 PM
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#1
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Guru
City: Sidney
Join Date: Feb 2015
Posts: 2,258
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Bow or stern down?
A buddy and I are debating underwater freefall in general and the El Faro in particular.
He says all sinking ships go down nose first.
He believes even if it starts stern down the bow will drop off and overtake because of the resistance to the stern.
I say it would depend on the weight of/in the stern vs. bow and the depth of fall.
Anyone here with real knowledge, math or physics to support either side?
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11-15-2015, 06:30 PM
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#2
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Guru
City: Bethlehem, PA
Vessel Name: Lady Kay V
Vessel Model: 1978 Hatteras 53MY
Join Date: Oct 2015
Posts: 1,098
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Now there's a first world problem.... No idea. Gut feeling says, all accidents are different. (They are in my business) So no clear cut conclusions. Sorry.
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11-15-2015, 06:37 PM
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#3
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,143
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Watch a bunch of WWII movies of torpedo hits...seems pretty well divided....
But they also involve hull damage...
What parameters are you looking for?
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11-15-2015, 07:02 PM
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#4
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Guru
City: Bethlehem, PA
Vessel Name: Lady Kay V
Vessel Model: 1978 Hatteras 53MY
Join Date: Oct 2015
Posts: 1,098
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Quote:
Originally Posted by psneeld
Watch a bunch of WWII movies of torpedo hits...seems pretty well divided....
But they also involve hull damage...
What parameters are you looking for?
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Gonna be hard to duplicate that...... I mean, I was offered a sub for sale when the curtain came down, but finding torpedoes.... that's another thing. Don't think Cabelas carries those.
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11-15-2015, 07:33 PM
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#5
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Guru
City: Fort Myers, FL... Summers in the Great Lakes
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 12,834
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Quote:
Originally Posted by Hawgwash
A buddy and I are debating underwater freefall in general and the El Faro in particular.
He says all sinking ships go down nose first.
He believes even if it starts stern down the bow will drop off and overtake because of the resistance to the stern.
I say it would depend on the weight of/in the stern vs. bow and the depth of fall.
Anyone here with real knowledge, math or physics to support either side?
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Are you assuming they go down keel down and land right side up? A lot don't. Ballast and cargo often shift in the sinking process. Most ships will strike the bottom before developing a sinking trajectory until the bottom is in the thousands of feet.
Interesting story: One of the WWII casualties we looked for was the SS William Rockefeller, one of the largest takers of that era. It was sunk off Hatteras NC. A survivor report from the National Archives indicated that the 572' tanker went vertical as she sank, picking up speed and disappearing like dropping a length of steel pipe vertically in the ocean. Since the tanker didn't stop from striking the ocean floor before disappearing from the surface, it was pointless to keep looking for it as it rested in over 500' of water (far to deep to dive back in the early '80s).
Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
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11-15-2015, 09:50 PM
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#6
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Guru
City: Sidney
Join Date: Feb 2015
Posts: 2,258
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Quote:
Originally Posted by psneeld
What parameters are you looking for?
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No real parameters, just need to prove him wrong.
He simply insists ALL sinkers turn bow down, with nothing more to go on than a bunch of WW II movies and concept of the bow being the point of least resistance.
I say, especially an the case of El Faro, if she had a belly full of vehicles and if she started stern down,they could easily have all jammed up in the in the stern and it could have been like a brick in a sock and taken her all the way stern first.
So, I just hoping someone here is a grad of the Maritime Academy of Hacky Sack, Morlacco and can help me win the case of beer.
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11-16-2015, 12:02 AM
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#7
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Senior Member
City: Houston
Vessel Name: Alegría
Vessel Model: Overblue 48
Join Date: Jun 2015
Posts: 237
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Remember Galileo and the Tower of Pisa. Everything falls at the same rate regardless of mass.
Why don't a feather and a marble fall at the same rate? Wind resistance.
So my theory is that, once a ship loses all bouyancy, it will descend pointy end down, if it doesn't break up. Many shipwrecks are found in pieces on the ocean floor, indicating that breaking up is common, probably due to differing bouyancy along the ship as different sections fill with water at different times.
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11-16-2015, 12:54 AM
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#8
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Senior Member
City: Offshore
Join Date: Jan 2015
Posts: 253
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Also, trapped air is likely common making a buoyancy issue that may play into it.
Especially commercial boats with water tight compartments.
__________________
Simplicity, is the ultimate sophistication.
Leonardo Da Vinci
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11-16-2015, 03:48 AM
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#9
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Senior Member
City: Hobart
Vessel Name: Theresa
Vessel Model: Cheoy Lee 66 LRMY
Join Date: Jun 2013
Posts: 118
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Jury is still out here.
After extensive tank testing I've decided the yellow end sinks first.
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11-16-2015, 05:38 AM
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#10
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Guru
City: Signal Mtn., TN
Vessel Name: Stella Maris
Vessel Model: Defever 44
Join Date: Feb 2012
Posts: 2,742
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Quote:
Originally Posted by Hawgwash
No real parameters, just need to prove him wrong.
He simply insists ALL sinkers turn bow down, with nothing more to go on than a bunch of WW II movies and concept of the bow being the point of least resistance.
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If he's talking about WWII Hollywood movies, weren't most of those "sinkings" staged in a pool or a tank?
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11-16-2015, 06:02 AM
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#11
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Guru
City: Fort Myers, FL... Summers in the Great Lakes
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 12,834
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Quote:
Originally Posted by angus99
If he's talking about WWII Hollywood movies, weren't most of those "sinkings" staged in a pool or a tank?
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Actually many of the WWII Sub casualties were slow to sink, measured in hours to days. Those that were within 50 miles of the coastal USA were sometimes photographed by reconnaissance planes doing coastal patrol. Lots of amazing pictures of ships sinking from WWII in the National Archives.
Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
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11-16-2015, 06:59 AM
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#12
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Guru
City: Tavernier, FL
Vessel Name: Volans
Vessel Model: 2001 PDQ MV 32
Join Date: Jan 2015
Posts: 580
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Remember the machinery spaces are generally near the stern. More dense than the crew quarters, hold, depending on cargo. In air, it doesn't matter but in water, more dense sinks faster than less dense. So tell you're buddy it depends on the ships outfitting. I've sunk plenty of model boats in the bathtub and have a master's degree in oceanography to back it up, haha
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11-16-2015, 10:49 AM
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#13
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Guru
City: Concrete Washington State
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 18,743
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I would think there would be many variables.
Did the water come in fast or slow and where in the hull did it come in? What was the CG when it sank and was there heavy stuff that could move around?
If a ship was heavy aft and was hit by a torpedo aft I'd put my money on stern first. Many probably do sink bow first because they hit something like a rock and filled w water at the bow and .......
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Eric
North Western Washington State USA
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11-16-2015, 11:14 AM
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#14
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Guru
City: Tri Cities, WA
Join Date: Nov 2012
Posts: 4,406
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I checked with King Neptune. Stern first due to the weight in the stern.
Straight from the horse's mouth!
:-)
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Mike and Tina
1981 Boston Whaler 13'
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11-16-2015, 07:04 PM
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#15
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Senior Member
Join Date: Jan 2012
Posts: 186
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If a tree falls in the forest, which way does it fall? Time to change the bong water.
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11-16-2015, 07:16 PM
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#16
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Guru
City: Sidney
Join Date: Feb 2015
Posts: 2,258
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Quote:
Originally Posted by chriscritchett
If a tree falls in the forest, which way does it fall? Time to change the bong water.
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Dave's not here.
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11-16-2015, 09:07 PM
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#18
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Guru
City: Bethlehem, PA
Vessel Name: Lady Kay V
Vessel Model: 1978 Hatteras 53MY
Join Date: Oct 2015
Posts: 1,098
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Quote:
Originally Posted by Hawgwash
Dave's not here.
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That's a toothpick MAN!
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